Added a module to measure plugin usage with Google Analytics.

Adds the EditorMeasurement class which allows plugin developers to
measure usage using Google Analytics.

At the moment the EditorMeasurement class is only enabled in the
unit test via the EditorMeasurement.GloballyEnabled flag.

Bug: 112723334
Change-Id: Ifbf7529accc74ee073ce8274f121770fb9ed043c

Author: Stewart Miles

source/VersionHandlerImpl/VersionHandlerImpl.csproj

@@ -55,6 +55,7 @@
   <ItemGroup>
     <Compile Include="src\Logger.cs" />
     <Compile Include="src\ExecutionEnvironment.cs" />
+    <Compile Include="src\EditorMeasurement.cs" />
     <Compile Include="src\FileUtils.cs" />
     <Compile Include="src\MultiSelectWindow.cs" />
     <Compile Include="src\PortableWebRequest.cs" />